[S390] dasd: add hyper PAV support to DASD device driver, part 1

Parallel access volumes (PAV) is a storage server feature, that allows
to start multiple channel programs on the same DASD in parallel. It
defines alias devices which can be used as alternative paths to the
same disk. With the old base PAV support we only needed rudimentary
functionality in the DASD device driver. As the mapping between base
and alias devices was static, we just had to export an identifier
(uid) and could leave the combining of devices to external layers
like a device mapper multipath.
Now hyper PAV removes the requirement to dedicate alias devices to
specific base devices. Instead each alias devices can be combined with
multiple base device on a per request basis. This requires full
support by the DASD device driver as now each channel program itself
has to identify the target base device.
The changes to the dasd device driver and the ECKD discipline are:
- Separate subchannel device representation (dasd_device) from block
  device representation (dasd_block). Only base devices are block
  devices.
- Gather information about base and alias devices and possible
  combinations.
- For each request decide which dasd_device should be used (base or
  alias) and build specific channel program.
- Support summary unit checks, which allow the storage server to
  upgrade / downgrade between base and hyper PAV at runtime (support
  is mandatory).

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 126 insertions, 232 deletions

diff --git a/drivers/s390/block/dasd_3990_erp.c b/drivers/s390/block/dasd_3990_erp.c
index c02f960eae1..c361ab69ec0 100644
--- a/drivers/s390/block/dasd_3990_erp.c
+++ b/drivers/s390/block/dasd_3990_erp.c
@@ -26,158 +26,6 @@ struct DCTL_data {
 
 /*
  *****************************************************************************
- * SECTION ERP EXAMINATION
- *****************************************************************************
- */
-
-/*
- * DASD_3990_ERP_EXAMINE_24
- *
- * DESCRIPTION
- *   Checks only for fatal (unrecoverable) error.
- *   A detailed examination of the sense data is done later outside
- *   the interrupt handler.
- *
- *   Each bit configuration leading to an action code 2 (Exit with
- *   programming error or unusual condition indication)
- *   are handled as fatal errors.
- *
- *   All other configurations are handled as recoverable errors.
- *
- * RETURN VALUES
- *   dasd_era_fatal	for all fatal (unrecoverable errors)
- *   dasd_era_recover	for all others.
- */
-static dasd_era_t
-dasd_3990_erp_examine_24(struct dasd_ccw_req * cqr, char *sense)
-{
-
-	struct dasd_device *device = cqr->device;
-
-	/* check for 'Command Reject' */
-	if ((sense[0] & SNS0_CMD_REJECT) &&
-	    (!(sense[2] & SNS2_ENV_DATA_PRESENT))) {
-
-		DEV_MESSAGE(KERN_ERR, device, "%s",
-			    "EXAMINE 24: Command Reject detected - "
-			    "fatal error");
-
-		return dasd_era_fatal;
-	}
-
-	/* check for 'Invalid Track Format' */
-	if ((sense[1] & SNS1_INV_TRACK_FORMAT) &&
-	    (!(sense[2] & SNS2_ENV_DATA_PRESENT))) {
-
-		DEV_MESSAGE(KERN_ERR, device, "%s",
-			    "EXAMINE 24: Invalid Track Format detected "
-			    "- fatal error");
-
-		return dasd_era_fatal;
-	}
-
-	/* check for 'No Record Found' */
-	if (sense[1] & SNS1_NO_REC_FOUND) {
-
-                /* FIXME: fatal error ?!? */
-		DEV_MESSAGE(KERN_ERR, device,
-			    "EXAMINE 24: No Record Found detected %s",
-                            device->state <= DASD_STATE_BASIC ?
-			    " " : "- fatal error");
-
-		return dasd_era_fatal;
-	}
-
-	/* return recoverable for all others */
-	return dasd_era_recover;
-}				/* END dasd_3990_erp_examine_24 */
-
-/*
- * DASD_3990_ERP_EXAMINE_32
- *
- * DESCRIPTION
- *   Checks only for fatal/no/recoverable error.
- *   A detailed examination of the sense data is done later outside
- *   the interrupt handler.
- *
- * RETURN VALUES
- *   dasd_era_none	no error
- *   dasd_era_fatal	for all fatal (unrecoverable errors)
- *   dasd_era_recover	for recoverable others.
- */
-static dasd_era_t
-dasd_3990_erp_examine_32(struct dasd_ccw_req * cqr, char *sense)
-{
-
-	struct dasd_device *device = cqr->device;
-
-	switch (sense[25]) {
-	case 0x00:
-		return dasd_era_none;
-
-	case 0x01:
-		DEV_MESSAGE(KERN_ERR, device, "%s", "EXAMINE 32: fatal error");
-
-		return dasd_era_fatal;
-
-	default:
-
-		return dasd_era_recover;
-	}
-
-}				/* end dasd_3990_erp_examine_32 */
-
-/*
- * DASD_3990_ERP_EXAMINE
- *
- * DESCRIPTION
- *   Checks only for fatal/no/recover error.
- *   A detailed examination of the sense data is done later outside
- *   the interrupt handler.
- *
- *   The logic is based on the 'IBM 3990 Storage Control  Reference' manual
- *   'Chapter 7. Error Recovery Procedures'.
- *
- * RETURN VALUES
- *   dasd_era_none	no error
- *   dasd_era_fatal	for all fatal (unrecoverable errors)
- *   dasd_era_recover	for all others.
- */
-dasd_era_t
-dasd_3990_erp_examine(struct dasd_ccw_req * cqr, struct irb * irb)
-{
-
-	char *sense = irb->ecw;
-	dasd_era_t era = dasd_era_recover;
-	struct dasd_device *device = cqr->device;
-
-	/* check for successful execution first */
-	if (irb->scsw.cstat == 0x00 &&
-	    irb->scsw.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))
-		return dasd_era_none;
-
-	/* distinguish between 24 and 32 byte sense data */
-	if (sense[27] & DASD_SENSE_BIT_0) {
-
-		era = dasd_3990_erp_examine_24(cqr, sense);
-
-	} else {
-
-		era = dasd_3990_erp_examine_32(cqr, sense);
-
-	}
-
-	/* log the erp chain if fatal error occurred */
-	if ((era == dasd_era_fatal) && (device->state >= DASD_STATE_READY)) {
-		dasd_log_sense(cqr, irb);
-	}
-
-	return era;
-
-}				/* END dasd_3990_erp_examine */
-
-/*
- *****************************************************************************
  * SECTION ERP HANDLING
  *****************************************************************************
  */
@@ -206,7 +54,7 @@ dasd_3990_erp_cleanup(struct dasd_ccw_req * erp, char final_status)
 {
 	struct dasd_ccw_req *cqr = erp->refers;
 
-	dasd_free_erp_request(erp, erp->device);
+	dasd_free_erp_request(erp, erp->memdev);
 	cqr->status = final_status;
 	return cqr;
 
@@ -224,15 +72,17 @@ static void
 dasd_3990_erp_block_queue(struct dasd_ccw_req * erp, int expires)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
+	unsigned long flags;
 
 	DEV_MESSAGE(KERN_INFO, device,
 		    "blocking request queue for %is", expires/HZ);
 
+	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 	device->stopped |= DASD_STOPPED_PENDING;
-	erp->status = DASD_CQR_QUEUED;
-
-	dasd_set_timer(device, expires);
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+	erp->status = DASD_CQR_FILLED;
+	dasd_block_set_timer(device->block, expires);
 }
 
 /*
@@ -251,7 +101,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_int_req(struct dasd_ccw_req * erp)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	/* first time set initial retry counter and erp_function */
 	/* and retry once without blocking queue		 */
@@ -292,11 +142,14 @@ dasd_3990_erp_int_req(struct dasd_ccw_req * erp)
 static void
 dasd_3990_erp_alternate_path(struct dasd_ccw_req * erp)
 {
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 	__u8 opm;
+	unsigned long flags;
 
 	/* try alternate valid path */
+	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 	opm = ccw_device_get_path_mask(device->cdev);
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 	//FIXME: start with get_opm ?
 	if (erp->lpm == 0)
 		erp->lpm = LPM_ANYPATH & ~(erp->irb.esw.esw0.sublog.lpum);
@@ -309,9 +162,8 @@ dasd_3990_erp_alternate_path(struct dasd_ccw_req * erp)
 			    "try alternate lpm=%x (lpum=%x / opm=%x)",
 			    erp->lpm, erp->irb.esw.esw0.sublog.lpum, opm);
 
-		/* reset status to queued to handle the request again... */
-		if (erp->status > DASD_CQR_QUEUED)
-			erp->status = DASD_CQR_QUEUED;
+		/* reset status to submit the request again... */
+		erp->status = DASD_CQR_FILLED;
 		erp->retries = 1;
 	} else {
 		DEV_MESSAGE(KERN_ERR, device,
@@ -320,8 +172,7 @@ dasd_3990_erp_alternate_path(struct dasd_ccw_req * erp)
 			    erp->irb.esw.esw0.sublog.lpum, opm);
 
 		/* post request with permanent error */
-		if (erp->status > DASD_CQR_QUEUED)
-			erp->status = DASD_CQR_FAILED;
+		erp->status = DASD_CQR_FAILED;
 	}
 }				/* end dasd_3990_erp_alternate_path */
 
@@ -344,14 +195,14 @@ static struct dasd_ccw_req *
 dasd_3990_erp_DCTL(struct dasd_ccw_req * erp, char modifier)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 	struct DCTL_data *DCTL_data;
 	struct ccw1 *ccw;
 	struct dasd_ccw_req *dctl_cqr;
 
 	dctl_cqr = dasd_alloc_erp_request((char *) &erp->magic, 1,
-					  sizeof (struct DCTL_data),
-					  erp->device);
+					  sizeof(struct DCTL_data),
+					  device);
 	if (IS_ERR(dctl_cqr)) {
 		DEV_MESSAGE(KERN_ERR, device, "%s",
 			    "Unable to allocate DCTL-CQR");
@@ -365,13 +216,14 @@ dasd_3990_erp_DCTL(struct dasd_ccw_req * erp, char modifier)
 	DCTL_data->modifier = modifier;
 
 	ccw = dctl_cqr->cpaddr;
-	memset(ccw, 0, sizeof (struct ccw1));
+	memset(ccw, 0, sizeof(struct ccw1));
 	ccw->cmd_code = CCW_CMD_DCTL;
 	ccw->count = 4;
 	ccw->cda = (__u32)(addr_t) DCTL_data;
 	dctl_cqr->function = dasd_3990_erp_DCTL;
 	dctl_cqr->refers = erp;
-	dctl_cqr->device = erp->device;
+	dctl_cqr->startdev = device;
+	dctl_cqr->memdev = device;
 	dctl_cqr->magic = erp->magic;
 	dctl_cqr->expires = 5 * 60 * HZ;
 	dctl_cqr->retries = 2;
@@ -435,7 +287,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_action_4(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	/* first time set initial retry counter and erp_function    */
 	/* and retry once without waiting for state change pending  */
@@ -472,7 +324,7 @@ dasd_3990_erp_action_4(struct dasd_ccw_req * erp, char *sense)
 				     "redriving request immediately, "
 				     "%d retries left",
 				     erp->retries);
-			erp->status = DASD_CQR_QUEUED;
+			erp->status = DASD_CQR_FILLED;
 		}
 	}
 
@@ -530,7 +382,7 @@ static void
 dasd_3990_handle_env_data(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 	char msg_format = (sense[7] & 0xF0);
 	char msg_no = (sense[7] & 0x0F);
 
@@ -1157,7 +1009,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_com_rej(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	erp->function = dasd_3990_erp_com_rej;
 
@@ -1198,7 +1050,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_bus_out(struct dasd_ccw_req * erp)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	/* first time set initial retry counter and erp_function */
 	/* and retry once without blocking queue		 */
@@ -1237,7 +1089,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_equip_check(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	erp->function = dasd_3990_erp_equip_check;
 
@@ -1279,7 +1131,6 @@ dasd_3990_erp_equip_check(struct dasd_ccw_req * erp, char *sense)
 
 		erp = dasd_3990_erp_action_5(erp);
 	}
-
 	return erp;
 
 }				/* end dasd_3990_erp_equip_check */
@@ -1299,7 +1150,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_data_check(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	erp->function = dasd_3990_erp_data_check;
 
@@ -1358,7 +1209,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_overrun(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	erp->function = dasd_3990_erp_overrun;
 
@@ -1387,7 +1238,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_inv_format(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	erp->function = dasd_3990_erp_inv_format;
 
@@ -1403,8 +1254,7 @@ dasd_3990_erp_inv_format(struct dasd_ccw_req * erp, char *sense)
 
 	} else {
 		DEV_MESSAGE(KERN_ERR, device, "%s",
-			    "Invalid Track Format - Fatal error should have "
-			    "been handled within the interrupt handler");
+			    "Invalid Track Format - Fatal error");
 
 		erp = dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);
 	}
@@ -1428,7 +1278,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_EOC(struct dasd_ccw_req * default_erp, char *sense)
 {
 
-	struct dasd_device *device = default_erp->device;
+	struct dasd_device *device = default_erp->startdev;
 
 	DEV_MESSAGE(KERN_ERR, device, "%s",
 		    "End-of-Cylinder - must never happen");
@@ -1453,7 +1303,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_env_data(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	erp->function = dasd_3990_erp_env_data;
 
@@ -1463,11 +1313,9 @@ dasd_3990_erp_env_data(struct dasd_ccw_req * erp, char *sense)
 
 	/* don't retry on disabled interface */
 	if (sense[7] != 0x0F) {
-
 		erp = dasd_3990_erp_action_4(erp, sense);
 	} else {
-
-		erp = dasd_3990_erp_cleanup(erp, DASD_CQR_IN_IO);
+		erp->status = DASD_CQR_FILLED;
 	}
 
 	return erp;
@@ -1490,11 +1338,10 @@ static struct dasd_ccw_req *
 dasd_3990_erp_no_rec(struct dasd_ccw_req * default_erp, char *sense)
 {
 
-	struct dasd_device *device = default_erp->device;
+	struct dasd_device *device = default_erp->startdev;
 
 	DEV_MESSAGE(KERN_ERR, device, "%s",
-		    "No Record Found - Fatal error should "
-		    "have been handled within the interrupt handler");
+		    "No Record Found - Fatal error ");
 
 	return dasd_3990_erp_cleanup(default_erp, DASD_CQR_FAILED);
 
@@ -1517,7 +1364,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_file_prot(struct dasd_ccw_req * erp)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	DEV_MESSAGE(KERN_ERR, device, "%s", "File Protected");
 
@@ -1526,6 +1373,43 @@ dasd_3990_erp_file_prot(struct dasd_ccw_req * erp)
 }				/* end dasd_3990_erp_file_prot */
 
 /*
+ * DASD_3990_ERP_INSPECT_ALIAS
+ *
+ * DESCRIPTION
+ *   Checks if the original request was started on an alias device.
+ *   If yes, it modifies the original and the erp request so that
+ *   the erp request can be started on a base device.
+ *
+ * PARAMETER
+ *   erp		pointer to the currently created default ERP
+ *
+ * RETURN VALUES
+ *   erp		pointer to the modified ERP, or NULL
+ */
+
+static struct dasd_ccw_req *dasd_3990_erp_inspect_alias(
+						struct dasd_ccw_req *erp)
+{
+	struct dasd_ccw_req *cqr = erp->refers;
+
+	if (cqr->block &&
+	    (cqr->block->base != cqr->startdev)) {
+		if (cqr->startdev->features & DASD_FEATURE_ERPLOG) {
+			DEV_MESSAGE(KERN_ERR, cqr->startdev,
+				    "ERP on alias device for request %p,"
+				    " recover on base device %s", cqr,
+				    cqr->block->base->cdev->dev.bus_id);
+		}
+		dasd_eckd_reset_ccw_to_base_io(cqr);
+		erp->startdev = cqr->block->base;
+		erp->function = dasd_3990_erp_inspect_alias;
+		return erp;
+	} else
+		return NULL;
+}
+
+
+/*
  * DASD_3990_ERP_INSPECT_24
  *
  * DESCRIPTION
@@ -1623,7 +1507,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_action_10_32(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	erp->retries = 256;
 	erp->function = dasd_3990_erp_action_10_32;
@@ -1657,13 +1541,14 @@ static struct dasd_ccw_req *
 dasd_3990_erp_action_1B_32(struct dasd_ccw_req * default_erp, char *sense)
 {
 
-	struct dasd_device *device = default_erp->device;
+	struct dasd_device *device = default_erp->startdev;
 	__u32 cpa = 0;
 	struct dasd_ccw_req *cqr;
 	struct dasd_ccw_req *erp;
 	struct DE_eckd_data *DE_data;
+	struct PFX_eckd_data *PFX_data;
 	char *LO_data;		/* LO_eckd_data_t */
-	struct ccw1 *ccw;
+	struct ccw1 *ccw, *oldccw;
 
 	DEV_MESSAGE(KERN_DEBUG, device, "%s",
 		    "Write not finished because of unexpected condition");
@@ -1702,8 +1587,8 @@ dasd_3990_erp_action_1B_32(struct dasd_ccw_req * default_erp, char *sense)
 	/* Build new ERP request including DE/LO */
 	erp = dasd_alloc_erp_request((char *) &cqr->magic,
 				     2 + 1,/* DE/LO + TIC */
-				     sizeof (struct DE_eckd_data) +
-				     sizeof (struct LO_eckd_data), device);
+				     sizeof(struct DE_eckd_data) +
+				     sizeof(struct LO_eckd_data), device);
 
 	if (IS_ERR(erp)) {
 		DEV_MESSAGE(KERN_ERR, device, "%s", "Unable to allocate ERP");
@@ -1712,10 +1597,16 @@ dasd_3990_erp_action_1B_32(struct dasd_ccw_req * default_erp, char *sense)
 
 	/* use original DE */
 	DE_data = erp->data;
-	memcpy(DE_data, cqr->data, sizeof (struct DE_eckd_data));
+	oldccw = cqr->cpaddr;
+	if (oldccw->cmd_code == DASD_ECKD_CCW_PFX) {
+		PFX_data = cqr->data;
+		memcpy(DE_data, &PFX_data->define_extend,
+		       sizeof(struct DE_eckd_data));
+	} else
+		memcpy(DE_data, cqr->data, sizeof(struct DE_eckd_data));
 
 	/* create LO */
-	LO_data = erp->data + sizeof (struct DE_eckd_data);
+	LO_data = erp->data + sizeof(struct DE_eckd_data);
 
 	if ((sense[3] == 0x01) && (LO_data[1] & 0x01)) {
 
@@ -1748,7 +1639,7 @@ dasd_3990_erp_action_1B_32(struct dasd_ccw_req * default_erp, char *sense)
 
 	/* create DE ccw */
 	ccw = erp->cpaddr;
-	memset(ccw, 0, sizeof (struct ccw1));
+	memset(ccw, 0, sizeof(struct ccw1));
 	ccw->cmd_code = DASD_ECKD_CCW_DEFINE_EXTENT;
 	ccw->flags = CCW_FLAG_CC;
 	ccw->count = 16;
@@ -1756,7 +1647,7 @@ dasd_3990_erp_action_1B_32(struct dasd_ccw_req * default_erp, char *sense)
 
 	/* create LO ccw */
 	ccw++;
-	memset(ccw, 0, sizeof (struct ccw1));
+	memset(ccw, 0, sizeof(struct ccw1));
 	ccw->cmd_code = DASD_ECKD_CCW_LOCATE_RECORD;
 	ccw->flags = CCW_FLAG_CC;
 	ccw->count = 16;
@@ -1770,7 +1661,8 @@ dasd_3990_erp_action_1B_32(struct dasd_ccw_req * default_erp, char *sense)
 	/* fill erp related fields */
 	erp->function = dasd_3990_erp_action_1B_32;
 	erp->refers = default_erp->refers;
-	erp->device = device;
+	erp->startdev = device;
+	erp->memdev = device;
 	erp->magic = default_erp->magic;
 	erp->expires = 0;
 	erp->retries = 256;
@@ -1803,7 +1695,7 @@ static struct dasd_ccw_req *
 dasd_3990_update_1B(struct dasd_ccw_req * previous_erp, char *sense)
 {
 
-	struct dasd_device *device = previous_erp->device;
+	struct dasd_device *device = previous_erp->startdev;
 	__u32 cpa = 0;
 	struct dasd_ccw_req *cqr;
 	struct dasd_ccw_req *erp;
@@ -1827,7 +1719,7 @@ dasd_3990_update_1B(struct dasd_ccw_req * previous_erp, char *sense)
 		DEV_MESSAGE(KERN_DEBUG, device, "%s",
 			    "Imprecise ending is set - just retry");
 
-		previous_erp->status = DASD_CQR_QUEUED;
+		previous_erp->status = DASD_CQR_FILLED;
 
 		return previous_erp;
 	}
@@ -1850,7 +1742,7 @@ dasd_3990_update_1B(struct dasd_ccw_req * previous_erp, char *sense)
 	erp = previous_erp;
 
 	/* update the LO with the new returned sense data  */
-	LO_data = erp->data + sizeof (struct DE_eckd_data);
+	LO_data = erp->data + sizeof(struct DE_eckd_data);
 
 	if ((sense[3] == 0x01) && (LO_data[1] & 0x01)) {
 
@@ -1889,7 +1781,7 @@ dasd_3990_update_1B(struct dasd_ccw_req * previous_erp, char *sense)
 	ccw++;			/* addr of TIC ccw */
 	ccw->cda = cpa;
 
-	erp->status = DASD_CQR_QUEUED;
+	erp->status = DASD_CQR_FILLED;
 
 	return erp;
 
@@ -1968,9 +1860,7 @@ dasd_3990_erp_compound_path(struct dasd_ccw_req * erp, char *sense)
 			 * try further actions. */
 
 			erp->lpm = 0;
-
-			erp->status = DASD_CQR_ERROR;
-
+			erp->status = DASD_CQR_NEED_ERP;
 		}
 	}
 
@@ -2047,7 +1937,7 @@ dasd_3990_erp_compound_config(struct dasd_ccw_req * erp, char *sense)
 	if ((sense[25] & DASD_SENSE_BIT_1) && (sense[26] & DASD_SENSE_BIT_2)) {
 
 		/* set to suspended duplex state then restart */
-		struct dasd_device *device = erp->device;
+		struct dasd_device *device = erp->startdev;
 
 		DEV_MESSAGE(KERN_ERR, device, "%s",
 			    "Set device to suspended duplex state should be "
@@ -2081,28 +1971,26 @@ dasd_3990_erp_compound(struct dasd_ccw_req * erp, char *sense)
 {
 
 	if ((erp->function == dasd_3990_erp_compound_retry) &&
-	    (erp->status == DASD_CQR_ERROR)) {
+	    (erp->status == DASD_CQR_NEED_ERP)) {
 
 		dasd_3990_erp_compound_path(erp, sense);
 	}
 
 	if ((erp->function == dasd_3990_erp_compound_path) &&
-	    (erp->status == DASD_CQR_ERROR)) {
+	    (erp->status == DASD_CQR_NEED_ERP)) {
 
 		erp = dasd_3990_erp_compound_code(erp, sense);
 	}
 
 	if ((erp->function == dasd_3990_erp_compound_code) &&
-	    (erp->status == DASD_CQR_ERROR)) {
+	    (erp->status == DASD_CQR_NEED_ERP)) {
 
 		dasd_3990_erp_compound_config(erp, sense);
 	}
 
 	/* if no compound action ERP specified, the request failed */
-	if (erp->status == DASD_CQR_ERROR) {
-
+	if (erp->status == DASD_CQR_NEED_ERP)
 		erp->status = DASD_CQR_FAILED;
-	}
 
 	return erp;
 
@@ -2127,7 +2015,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_inspect_32(struct dasd_ccw_req * erp, char *sense)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 
 	erp->function = dasd_3990_erp_inspect_32;
 
@@ -2149,8 +2037,7 @@ dasd_3990_erp_inspect_32(struct dasd_ccw_req * erp, char *sense)
 
 		case 0x01:	/* fatal error */
 			DEV_MESSAGE(KERN_ERR, device, "%s",
-				    "Fatal error should have been "
-				    "handled within the interrupt handler");
+				    "Retry not recommended - Fatal error");
 
 			erp = dasd_3990_erp_cleanup(erp, DASD_CQR_FAILED);
 			break;
@@ -2253,6 +2140,11 @@ dasd_3990_erp_inspect(struct dasd_ccw_req * erp)
 	/* already set up new ERP !			      */
 	char *sense = erp->refers->irb.ecw;
 
+	/* if this problem occured on an alias retry on base */
+	erp_new = dasd_3990_erp_inspect_alias(erp);
+	if (erp_new)
+		return erp_new;
+
 	/* distinguish between 24 and 32 byte sense data */
 	if (sense[27] & DASD_SENSE_BIT_0) {
 
@@ -2287,13 +2179,13 @@ static struct dasd_ccw_req *
 dasd_3990_erp_add_erp(struct dasd_ccw_req * cqr)
 {
 
-	struct dasd_device *device = cqr->device;
+	struct dasd_device *device = cqr->startdev;
 	struct ccw1 *ccw;
 
 	/* allocate additional request block */
 	struct dasd_ccw_req *erp;
 
-	erp = dasd_alloc_erp_request((char *) &cqr->magic, 2, 0, cqr->device);
+	erp = dasd_alloc_erp_request((char *) &cqr->magic, 2, 0, device);
 	if (IS_ERR(erp)) {
                 if (cqr->retries <= 0) {
 		        DEV_MESSAGE(KERN_ERR, device, "%s",
@@ -2305,7 +2197,7 @@ dasd_3990_erp_add_erp(struct dasd_ccw_req * cqr)
                                      "Unable to allocate ERP request "
 				     "(%i retries left)",
                                      cqr->retries);
-			dasd_set_timer(device, (HZ << 3));
+			dasd_block_set_timer(device->block, (HZ << 3));
                 }
 		return cqr;
 	}
@@ -2319,7 +2211,9 @@ dasd_3990_erp_add_erp(struct dasd_ccw_req * cqr)
 	ccw->cda      = (long)(cqr->cpaddr);
 	erp->function = dasd_3990_erp_add_erp;
 	erp->refers   = cqr;
-	erp->device   = cqr->device;
+	erp->startdev = device;
+	erp->memdev   = device;
+	erp->block    = cqr->block;
 	erp->magic    = cqr->magic;
 	erp->expires  = 0;
 	erp->retries  = 256;
@@ -2466,7 +2360,7 @@ static struct dasd_ccw_req *
 dasd_3990_erp_further_erp(struct dasd_ccw_req *erp)
 {
 
-	struct dasd_device *device = erp->device;
+	struct dasd_device *device = erp->startdev;
 	char *sense = erp->irb.ecw;
 
 	/* check for 24 byte sense ERP */
@@ -2557,7 +2451,7 @@ dasd_3990_erp_handle_match_erp(struct dasd_ccw_req *erp_head,
 			       struct dasd_ccw_req *erp)
 {
 
-	struct dasd_device *device = erp_head->device;
+	struct dasd_device *device = erp_head->startdev;
 	struct dasd_ccw_req *erp_done = erp_head;	/* finished req */
 	struct dasd_ccw_req *erp_free = NULL;	/* req to be freed */
 
@@ -2569,13 +2463,13 @@ dasd_3990_erp_handle_match_erp(struct dasd_ccw_req *erp_head,
 			      "original request was lost\n");
 
 		/* remove the request from the device queue */
-		list_del(&erp_done->list);
+		list_del(&erp_done->blocklist);
 
 		erp_free = erp_done;
 		erp_done = erp_done->refers;
 
 		/* free the finished erp request */
-		dasd_free_erp_request(erp_free, erp_free->device);
+		dasd_free_erp_request(erp_free, erp_free->memdev);
 
 	}			/* end while */
 
@@ -2603,7 +2497,7 @@ dasd_3990_erp_handle_match_erp(struct dasd_ccw_req *erp_head,
 				    erp->retries, erp);
 
 			/* handle the request again... */
-			erp->status = DASD_CQR_QUEUED;
+			erp->status = DASD_CQR_FILLED;
 		}
 
 	} else {
@@ -2636,9 +2530,8 @@ dasd_3990_erp_handle_match_erp(struct dasd_ccw_req *erp_head,
 struct dasd_ccw_req *
 dasd_3990_erp_action(struct dasd_ccw_req * cqr)
 {
-
 	struct dasd_ccw_req *erp = NULL;
-	struct dasd_device *device = cqr->device;
+	struct dasd_device *device = cqr->startdev;
 	struct dasd_ccw_req *temp_erp = NULL;
 
 	if (device->features & DASD_FEATURE_ERPLOG) {
@@ -2704,10 +2597,11 @@ dasd_3990_erp_action(struct dasd_ccw_req * cqr)
 		}
 	}
 
-	/* enqueue added ERP request */
-	if (erp->status == DASD_CQR_FILLED) {
-		erp->status = DASD_CQR_QUEUED;
-		list_add(&erp->list, &device->ccw_queue);
+	/* enqueue ERP request if it's a new one */
+	if (list_empty(&erp->blocklist)) {
+		cqr->status = DASD_CQR_IN_ERP;
+		/* add erp request before the cqr */
+		list_add_tail(&erp->blocklist, &cqr->blocklist);
 	}
 
 	return erp;